There is a continuing need for lighting apparatus which is low-cost and energy efficient. LEDs provide light sources which are energy efficient and advances in LED technology are providing even greater such efficiencies. One advantage of using LEDs as light sources is simply that the smaller size of such sources translate into lower material usage within fixtures containing such sources, thus yielding the attendant cost-efficiency.
Preferred performance requirements for lighting systems for various uses involve freedom of “light spillage” into areas not intended to be lit. For example, it is preferred that roadway and parking lot lighting systems have excellent light distribution over areas which are to be lighted, but neighboring regions are as free of light as possible. More specifically, there is a need to be able to direct light in a downward and preferential lateral direction while avoiding so-called trespass lighting on neighboring property, while providing lighting to the roadways or parking lots. Satisfying such concerns can be difficult when LEDs are used as light sources, particularly given the fact that in such cases many LEDs are used in individual fixtures.
Various LED lighting fixtures with either light shielding or gasket layers have been developed. Examples of such prior art fixtures are those disclosed in the following United States patents: U.S. Pat. No. 7,019,334 (Yatsudia, et al), U.S. Pat. No. 6,972,439 (Kim, et al.), Patent Publication Nos: US 2006/0175626 (Wall Jr.), US 2006/0158080 (Nakano et al.) and patent application Ser. No. 11/743,961 (Wilcox, et al.) and Ser. No. 11/744,807 (Wilcox, et al.).
LED fixtures in the prior art having shields and/or gasket layers have certain shortcomings and disadvantages to which this invention is addressed. In particular, there is a need for an improved LED light fixture with a directional shield that facilitates accurate manufacture while having an improved effectiveness in light distribution, including avoidance of light distribution to a non-preferential side. It would be desirable that an LED light fixture with directional shielding which is cost-effective in manufacture be able to provide a high level of output for lighting large areas in a preferential direction while minimizing light in a non-preferential direction. Protection against various environmental factors is also rendered difficult for LED general illumination products which necessarily utilize a large number of LEDs—sometimes plural LED modules with each module having many LED packages thereon.